Various prior art devices have been suggested for reducing aerodynamic drag of a moving vehicle, and more particularly to apparatus for reducing air drag on flat-nosed trailer trucks, railroad cars, and other similar blunt-nosed, towed vehicles which present a substantially broad aerodynamically resistant surface in the direction of travel of the vehicle. Of these prior art devices, there are disclosures of various provision of air vanes or fins around the edges of the cargo carrying portion of the vehicle to deflect the impinging air stream. Such devices include large blister-shaped deflectors provided with an opening for collecting impinging air, and a conduit means extending along the trailer to exit collected air at the rear portion of the trailer. Obviously, this requires a substantial modification to the trailer or similar blunt-nosed towed vehicle. Other prior art devices, although successful in varying degrees in reducing the aerodynamic resistance or drag on a vehicle, are deficient to the extent that they require either substantial modification to the towed vehicle to employ the devices, or necessitate use of a combination of several devices to achieve reduction of aerodynamic resistance in both the head flow and cross flow of air. The other prior art devices substantially increase the cost of air resistance reduction.